Improvement in floor-clamps



a. G. SHAW.

FLOOR-CLAMP;

PatenPedJ' uneIS, 1876.

STATES GEORGE Gr. SHAW, OF BIDDEFORD, MAINE.

IMPROVEMENT IN FLOOR-CLAMPS.

Specification forming part of Letters Patent No.

178,677, dated June 13, 1876 application filed April 5, 1876.

To all whom it may concern Be it known that I, GEORGE Gr. SHAW, of Biddeford, in the county of York, State of Maine, have invented a certain new and useful Improvement in Floor Clamps, of which the following is a description sufficiently full, clear, and exact to enable any person skilled in the art or science to which my invention appertains to make and use the same, reference being had to the accompanying drawing, forming a part of this specification, in which- Figure l is an isometrical perspective view, and Fig. 2 a vertical longitudinal section taken on the line a; in Fig. 1.

Like letters of reference indicate corresponding parts in the different figures of the drawi n g.

My invention relates to that class of tools or implements which are employed by carpenters for jacking or setting the boards in laying floors and similar work; and consists in a novel construction and arrangement of the parts, as hereinafter more fully set forth and claimed, by which a more effeciive device is produced than is now in ordinary use.

The nature and operation of my invention will be readily understood by all conversant with such matters from thefollowing description.

In the drawing, A represents the body of the jack, which is slotted longitudinally at L to receive the serrated sliding bar B. A lever, G, is pivoted at H in uprights or standards rising from the sides of the body A, and

jointed to thelowerend of this lever, at 6, there is an actuating-pawl, E. A retaining-pawl, I, is pivoted at J, and provided with the spring K, acting expansively to keep it in contact with the teeth on the bar B. Acrossbar, D, preferably cast integral with the body of the jack, is arranged at the bifurcated end of the body A to strengthen the same, and is ex tended upwardly to form a guard or stop for the pawl E. A spring, a, is secured to the upper side of the lever Gr near the pivot H. The object of this spring is to force the pawl E into contact with the teeth on the bar B when the lever G is in the position shown in Fig. 2, the action of the spring being inconstant at other times. The bar B is fitted to work in proper ways or rundlets (not shown) within the body A, which is provided upon one of its sides with spurs mm, to retain it in any desired position when the implement is employed in laying floors.

In the use of my improved implement as a floor-jack, it is first secured firmly in a horizontal position by means of the spurs m m, which, forthat purpose, may be caused to intersect with the under floor or floor-timbers; or, when convenient. the foot d may be permitted to abut against a post or other immovableobject, in which case the spurs will not be required. The bar B is then moved until its head or top 2 is brought in contact with the edge of the board, or with a guard interposed in the usual manner, when, by rocking or vibrating the lever G, the pawl E, acting upon the bar, will force the board into a proper position for nailing, where it will be held by the pawl I, all in a manner which will be readily understood from the foregoing description.

The lever G is pivoted at such a distance above the plane of the bar B as to permit the joint 6 of the pawl E to pass between the bar and the center of motion of the lever when the lever is thrown forward or upward, as shown in Fig. 2.

The object of this construction and arrangement of the pawl and lever is to obtain a duplex ordouble action of the pawl. Forin stance, the lever beingin the position shown in Fig. 2, if nowit is thrown back toward the pawl I, the joints will pass a line drawn at right angles to the bar through the pivot H, and the pawl E will continue to act on the bar until the joint arrives at a line drawn in parallelism with the bar through the pivot H, when the pawl will cease to act, and, as the lever continues its course, will fall by gravitation and take a fresh hold of the bar. It, now, the movement of the lever is reversed, the pawl E will again act upon the bar until the joint e passes between the bar and pivot H, when it will be released preparatory to taking another hold, the pawl I retaining the bar in its advanced position whenever the pawl E ceases to act.

It is sometimes desirable in the use of the implement to detach the pawl I, in order to render it inconvenient to operate the pawl directly. To obviate this difficulty the outer end of the pawl is elongated to such an extent Having thus explained my invention, what I claim is- In a floor-jack, the lever G, pawls E and I, and serrated bar B, constructed as described, so that the pivoted head of the pawl E will pass and repass a line between the fulcrum of the lever and the bar as theleveris alternately thrown backward and forward, as and for the purpose set forth.

' GEORGE G. SHAW.

Witnesses:

OTIS T. GAREY GEORGE L. STROUT.

[ SPIV 

